1993 F-150, 351 motor

Recently it's developed a squeak under the hood. Not the deafening squeal of a slipping belt because 1) the belt only has like 10k miles on it and 2) deflection is spot-on to specs. The tensioner is right where it should be. And it's more intermittent. Rapid, but intermittent, not a constant squeak. It varies with engine speed, not vehicle speed. I can't pinpoint the source of the noise, but if I had to guess a bearing on some pulley is going. It seems to get a little quieter once the engine is warm, but still loud enough to hear in the cab providing the radio isn't blasting. Neither electrical load nor using A/C affects the noise, which leads me to think it's either the idler wheel bearing, or the tensioner wheel bearing.

Whaddya think? Does that guess seem right.

 

I would check around your air filter tubing. It may be rubbing. Look for any hoses that have bad shiney spots.

 

My advise = remove belt and check all bearings, especially the alternator. Take a wire brush and brush all the pulleys to remove deposits in the grooves. Check to see that the belt is not bottoming-out on any worn out pulleys. Re-assemble and check. If it is still squealing, replace the idler tensioner.

 

Check harmonic balancer (crank pulley). Check really good, the rubber used to put it together could be getting bad and cracked, a rare problem but NOT good.

 

Thanks, I'll pull the belt this weekend and give the pulleys a once over, see if I can't pinpoint the source.

 

While the belt is removed, start it and see if the noise is gone. Run it no longer than about 1 min. If the noise is gone, spin all pulleys by hand. If no noise, put the belt on and if the noise is there (BE CAREFUL) and while it is running hold a bar of soap and make contact with the belt. If the soap quiets the belt, the belt could be worn and or one of the pulleys may be a little out of alignment. If one of the pulleys are out of alignment what happens is the belt rubs the pulley when it is entering it and leaving it making an aweful noise. Sometimes this noise will sound almost like a grinding noise instead of a squeeling noise. Been there done that. Hope this helps.

 

Worn out idler tensioner's are almost always the cause of this problem. They're easy to fix. 1 bolt.

 

Just wondering if you ever found the cause of your squealing problem? I, today, now seem to have the same issue.

Any help would be cool. Thanks.